Apparatus for distilling ammonia



NOV. 30, 1954 c, OTTQ APPARATUS FOR DISTILLING AMMONIA 4 Sheets-Sheet 1 Filed Sept. 16 ,11950 INVENTOR CFI RL OTTO BY )m/uM ATTORNEY Nov. 30, 1954 c. or'ro APPARATUS FOR DISTILLING AMMONIA 4 Sheets-Sheet 2 Filed Sept. 16, 1950 INVENTOR CFI RL OTTO rural- 1:13:11

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u len 22 BY Vaf/w/ ATTORNEY Nov. 30, 1954 c. OTTO APPARATUS FOR DISTILLING AMMONIA A 4 Sheets-Sheet 5 Filed Sept. 16, 1950 NVENTOR CARL OTTO ATTORNEY NCW."` 30, 1954 Q OTTO 2,695,870

APPARATUS FOR DISTILLING AMMONIA Filed Sept. 16. 1950 4 Sheets-Sheet 4 INVENTOR CHRI. OTTO VLM.

ATTORNEY United States Patent 2,695,870 Patented Nov. 30, 1954 ice .The general object of the present invention is to provide an improved method of distilling ammonia liquor and an improved ammonia still for use in such distillation.

' The invention was primarily devised for, and is of especial utility in the distillation of the ammonia liquor recovered `in cooling and eliminating tar from coke oven gas. Such ammonia liquor includes ammonia dissolved in water and ammonia compounds which are readily decomposed when heated to moderate steam temperatures, and also includes relatively stable or fixed ammonium compounds such as ammonium chloride and ammonium sulphate which cannot be decomposed without the aid of a stronger alkali. The latter is usually milk of lime. It has long been regular practice to recover ammonia from ammonia liquor of the above mentioned character in column stills of the well known bubble still type.

The primary object of the present invention is to simplify and reduce the cost of distilling ammonia liquor, and to reduce the bulk and construction cost of the distilling apparatus used, by spraying the liquor in finely subdivided or atomized form at successively lower levels into a gas stream containing steam and distillates and owing upward through a gas passage of relatively small ow resistance, so that the distillation of the liquor is rapidly effected by the contact of the ascending gaseous stream with the minute particles of liquor sprayed into the stream.

In the preferred form of the invention, the continuous gas passage comprises a series of vertically displaced substantially unobstructed spray chambers and the liquor sprayed into each spray chamber is collected in a liquor receiver directly beneath the lower end portion of that spray chamber. A separate liquor defiector extends upward away from each liquor receiver and across the portion of the gas passage alongside said receiver, to deflect down fiowing liquor away from said gas passage portion and into the receiver, and each of said defiectors is formed with gas passages through which the lower end portion of the spray chamber directly above the adjacent receiver is in communication with the upper portion of the spray chamber including the passage portion along said receiver. In operation the liquor treated is passed successively through the receivers at successively lower levels, and liquor is continuously withdrawn from each receiver and sprayed into the spray chamber directly above the receiver.

A further specific object of the invention is to provide distilling apparatus including simple and effective provisions for minimizing risk of having the liquor outlets from the liquor receivers clogged by solids tending to accumulate in the receivers, and facilitating the inspection and cleaning of the receivers.

A further specific object of the invention is to provide improved means for adding lime to the liquor treated in the fixed still portion of the distilling apparatus, and for agitating and remixing the liquor and entrained solids passing through that portion of the distilling apparatus.

The invention in its preferred form is characterized by the separation of a vertically elongated still column or tower into a plurality of superposed sections each having a vertical length greater than the diameter of the column or tower, and by the location in one end portion of each section of nozzle means for spraying liquid in a general vertical direction toward the other end portion of the section.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For

a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had to the accompanying drawing and descriptive matter in which I have illustrated and described preferred embodiments of the invention.

Of the drawings:

Fig. 1 is a diagrammatic elevation of an improved ammonia still comprising superposed free ammonia and fixed still sections;

Fig. 2 is a plan section on the line 2-2 of Fig. l;

F Fig. 3 is a partial elevation taken at right angles to Fig. 4 is a partial section on the line 4-4 of Fig. 1;

Fig. 5 is a plan section taken on the line 5-5 of Fig. 4;

Fig. 6 is an elevation of a fixed still;

Fig. 7 is an elevation of a free still;

Fig. 8 is an elevation of a modified form of a free still;

Fig. 9 is a reproduction in section of the lower portion of the still shown in Fig. 8;

Fig. 10 is a section on the line 10-10 of Fig. 9;

Fig. 1l is an elevation of the upper end portion of xed still and associated feed liquor piping;

Fig. 12 is an elevation in section of another form of fixed still;

Fig. 13 is a section on the line 13-13 of Fig. 12;

Fig. 14 is a section on the line 14-14 of Fig. 12; and

Fig. 15 is a sectional elevation of a modified form of free still.

In Figs. 1-5, I have illustrated a desirable ammonia still embodiment of my invention, in which a single vertically elongated tower, or distilling column, includes a lower fixed still unit A, and an upper free still unit B directly superposed on the unit A. The .two units may be separately constructed as shown in Figs. 6 and 7, which illustrate fixed and free still units A' and B', respectively.

The tower structure shown in Fig. l comprises a bottom section 1, a plurality of similar intermediate sections 2, 3, 4, 5, 6, "i, 8 and 9, and an upper end section 10. Each of said tower sections 1-10 is circular in horizontal cross sectionand the intermediate sections may be, and as shown are counterparts of one another. Each of said sections is formed with an out turned flange at each end for bolted connection to the adjacent sections, or, in case of the lower end of the lower section 1 and the upper end of the upper section 10, for the attachment thereto of lower and upper end heads 11 and 11a, respectively. The base section 1 and the intermediate tubular sections 2, 3, 4, 5 and 6, collectively form the fixed still tower unit A, while the intermediate sections 7, 8 and 9, and the top section 11b form the free still tower unit B. In Fig. 1, the lower end of the bottom section 7 of the free still unit B opens directly into the upper end of the top section 6 of the fixed still unit A.

Each of the intermediate tower sections 2-9 is formed intermediate its ends, with an internal liquid receiver or collecting chamber 12, and with an external outlet nozzle 13. As shown, each outlet nozzle 13 is adapted to serve as a manhole providing access to the interior of the tower adjacent each receiver 12, particularly for inspection and cleaning purposes and forming part of the connection to the receiver space of a pump C for withdrawing liquld from said space. Each receiver 12 is open at its upper end, to a spray chamber directly above it, and is open at its outer side to an adjacent tower outlet nozzle 13. As shown, the lateral wall of each receiver 12 comprises a portion of the cylindrical wall ofthe corresponding tower section to which the corresponding outlet nozzle is connected7 and a wall part 14. Each wall part 14 comprises a short vertical upper portion 14 and a fiat plate or body portion inclined downwardly from the horizontal and welded at its edge to the tower or tank wall.

Each outlet nozzle 13 has the inner wall of its bottom portion at the level of the upper side of the lowermost portion of the plate 14, and as shown, the diameter of each outlet nozzle 13 is somewhat less than the vertical extent of the corresponding liquid receiver 12. In normal operation, a separate pump C continuously withdraws liquid from each, except the uppermost, of the receivers 12, through the corresponding outlet nozzle 13. As shown each pump C has its inlet pipe 17 in communication with a corresponding receiver 12 through a port 15 in the lower portion of a plate or head 16 extending across and detachably secured to the outer end of the corresponding outlet nozzle 13.

With the receiver wall portions formed by the tower shell portion and by the inclined member as described, solid material entering each receiver 12 at its upper end, has a tendency to move into the lowermost portion of the receiver as a result of the entraining action of the liquid in the receiver and moving toward the port 15 in the head 16, and as a result of gravitational action. Any solid particle engaging the portion of the receiver wall formed by the plate 14, or by the tank shell, tends to slide down, under the action of gravity, out of the receiver 12 and into the adjacent bottom portion of the nozzle 13. When a head 16 is disconnected from the ange of the corresponding nozzle 13, the latter can serve its manhole purpose of permitting access to the interior of the tower for cleaning or other purposes. As shown in Fig. 8, and other iigures, a separate manhole opening 13D may be formed in each tower section at a level above the receiver therein to permit access to the latter and also to the adjacent baille plates.

The liquid passed, as is hereinafter explained, into the upper end of the distilling column for treatment therein, is collected in the uppermost receiver 12, which is in section 9, and from which the liquor is passed into the next lower receiver 12 in the section 3. Each of the receivers 12, except the uppermost, not only supplies the liquor sprayed into the spray chamber above it, but also discharges liquor into the subjacent portion of the distilling column. The liquor withdrawn by each pump C from a corresponding receiver 12, is passed through the pump outlet pipe 18 to a spray nozzle E which discharges the liquid in the form of a downwardly directed liquid spray, into the upper portion of a spray chamber directly above the receiver from which the liquor was withdrawn. The upper portion of each spray chamber extends upward past the next highest receiver 12, and overlaps the portion of the spray chamber directly above the last mentioned receiver. The upper portion of the lowermost spray chamber overlaps the upper portion of a scrubbing chamber in the lower end tower sections 1 and 2. Similarly the upper portion of the uppermost spray chamber overlaps the lower portion of a spray chamber in the upper end tower sections 9 and 10.

A baille or louver structure F is interposed between each two overlapping spray chamber portions to cause all liquor sprayed into each spray chamber to pass into the liquid collecting receiver below that chamber. As shown, each baille or louver F comprises parallel, llat, downwardly inclined, dellector plates 19, 2) and 21 at successively lower levels, and having edge portions welded to the surrounding tower section. The uppermost deilector plate 19 has a curved upper edge 19 in continuous engagement with the tower shell from one end of the plate to the other, as clearly appears in Fig. l5. The intermediate and lower deflector plates 20 and 21 are each laterally displaced7 relative to the detlector plate immediately above it, from the side of the tower shell engaged by the edge 19 of the upper plate 19. The later displacement of the detlector plates is such that the upper edge of the intermediate plate 20 has its upper edge overlapped by a lower portion of the upper plate 19. and has its lower edge overlapping the upper portion of the plate 21. The lower portion of the plate 21 extends across the upper edge portion 14' of the wall part 14 of the subjacent receiving chamber 12, into which liquid falling onto each of the three plates is deflected.

The plates 19, 20 and 21 are spaced apart to provide gas channels for the passage of vapors and gases from the sprav chamber extending below the associated receiver 12 into the spray chamber having its lower end directly above said receiver. As shown in Fig. 2. the width of each of the baille plates 19, 20 and 21 is appreciably less than the distance from the axis to the periphery of the tower. ln consequence, the lower edge of the battle plate 19 is displaced for a substantial distance from the tower The lower edge of the lowermost baille 21 overlaps the upper edge of the subiacent wall 14', and the lower edges of the balles 21B and 21 overlap the upper edges of the subjacent baffles 19 and 20, respectively. ln consequence, all of the liquor sprayed into the tower by each spray nozzle E collects in the subjacent' collecting chamber or receiver 12 or 12A.

In the forms of construction shown, the lower tower section 1 of Fig. l is like that of Fig. 6, and is better illustrated in Fig. 6, which is on a somewhat larger scale than Fig. l. In each of Figs. l and 6, the lower tower section 1 is formed with diametrically opposed outlet nozzles 13A and 13B, and is divided by an uprising partition wall 22 into separate liquid spaces at opposite sides of the wall 22, and respectively communicating with the outlets 13A and 13B. An inclined baille plate FA prevents liquor discharged by the spray nozzle E into the upper portion of the lowermost spray chamber from passing directly into the liquor space at the side of the wall 22 in communication with the outlet 13B. The last mentioned space receives liquor collecting in the receiving space at the left of the partition or weir 22 and ilowing over the top of the latter to the outlet nozzle 13B. Ordinarily the liquor passing away from the still through the nozzle 13B is discharged to waste.

Liquor is drawn through the nozzle 13A from the liquor collecting space in the section 1 at the left of the partition 22, and, as shown in Fig. 1, is forced under pressure to the spray nozzle E in the upper portion of* the spray chamber by a steam ejector CA. The latter has inlet and outlet pipes 24 and 25, and is supplied with steam by a pipe 25. The steam so supplied serves as the motor fluid for moving liquid from the section 1 to the spray nozzle E in the lowcrmost scrubbing chamber. The steam supplied also serves as a source of heat and vapor for maintaining the still action required to separate ammonia vapors from the liquor sprayed into the scrubbing chamber. The steam passes away from the ejector CA in such volume and under such pressure that the liquor passing out of the discharge pipe 25 will be effectively vaporized even though the spray nozzle E is removed. When more steam is needed in the tower, than is supplied through the ejector CA, the pump C drawing liquor from the receiver 12 in the tower section 2 may be replaced by a steam ejector like the ejector CA and having a separate steam supply connection.

The ammonia liquor treated in the tower shown in Fig. l, is sprayed into the upper portion of the upper end section 10 through a pipe 27 and a spray nozzle 23. As shown, a perforated horizontal liquor distributor 29, iS located in the upper end portion of the section 10 below the nozzle 23. The section 10 is provided at its upper end with a vapor outlet 30, which normally passes the escaping vapors into a dephlcgmator, not shown in Fig. l. The lower end of the section 10 is open across the entire cross sectional area of the tower to the upper end of the section 9. The section 9 differs from the subjacent sections 2-8 only in that the outer end of its nozzle portions 13 is closed by a plate or head 16.

Since in normal operation liquid is being continually passed into the upper section 10 through the supply pipe 2S, there is necessarily a continuous down flow of liquid through the tower from the section 10 into the section 1. This means that each of the receivers 12 associated with the sections 2-8, receives more liquid from the spray chamber above it, than is withdrawn from said receiver by the associated pump C or steam ejector CA. In accordance with the present invention, the liquid collecting in the receiver 12 in the lower end of section 9, is passed from that receiver to the receiver 12 in the subjacent ection S, by an external discharge conduit G. Similarly each of the receivers 12 in the tower sections 2 8 discharges excess liquid from its upper end portion into the subjacent liquid receiver 12. through a corresponding external conduit G or by overflowing the edge 14 of the receiver wall.

As shown in Fig. l, the receivers 12 in the tower sections 2, 4, 6 and S have their lower ends and their associated outlet nozzles 13 at the right side of the tower, while the receivers 12 and 12A in the tower sections 1, 3, 5, 7 and 9 have their lower ends at the left of the tower. When the pipe connections between the various pumps C and the spray nozzles to which they supply liquor are of the type shown in Fig. l, the arrangement of the receiver outlets alternately at opposite sides of the tower has the advantage of simplifying the pipe connections. As will be apparent, however, the various receivers may all have their outlets at the same side of the tower, as is shown, for example, in the upper portion 0f Fig. 12. While it is convenient to have the external .overilow pipes C arranged alternately at opposite sides of the tower as shown in Fig. 3, the pipes G may be all arranged at the same side of the tower. The arrangement of the overflow condrits G outside of the tower and connected through readily separable pipe joints to nozzles g integrally connected to the tower shell as it facilitates the cleaning out of the overflow connections `if and when such cleaning is necessary. However, the

overflow conduits G may be replaced by internal overflow conduits GA as shown in Fig. 7.

In the desirable form of the invention shown in Fig. 1, milk of lime is passed into the upper end of the fixed still section A by means of a lime supply pipe H which passes the lime under suitable pressure into the outlet pipe 18 of the pump C discharging into the tower section 6 at the upper end of the unit A. To agitate and repeatedly remix the liquor and solids recirculated by the pumps C associated with the fixed still unit A, the outlet pipes 18 of some, at least, of those pumps may advantageously include a mixing nozzle I of the type illustrated in Figs. 4 and 5. As shown in Figs. 4 and 5, the mixing nozzle I is of the well known type disclosed in the Jacobsen Patent 1,637,697 of August 2, 1927. Each mixing nozzle I comprises an element with a peripheral flange 31 clamped between the outturned fianges of tubular sections 18a included in the corresponding pump outlet pipe 18, and of greater cross section than the remainder of the pipe 18.

As shown, each nozzle element I is a one piece casting of high silicon iron or other metallic alloy suitably resistant to corrosion, and comprises an inlet section ia at one side, and a mixing portion ib at the other side of its ange portion 31. The inlet portion a comprises an intermediate ring-like portion 32 fitting easily in the surrounding pipe section as shown in Fig. 5, and a tapered portion at the inlet end of said ring portion, and is formed with inclined inlet passages 33 and a main central inlet passage 34. The portion of the main inlet passage 34 adjacent the flange 31 diminishes in cross section as it approaches the mixing portion ib. A pair of transverse partitions 35 divided the main inlet passage into four parts. The mixing portion ib comprises a cavity or circular chamber 36 partly surrounded by the flange 31 and into which the reduced end of the main inlet passage opens. The wall at the side of the chamber 36 remote from the inlet portion ia is formed with four cylindrical outlet openings 37. A central conical projection 38 from the front wall of the chamber 36 of the outlet portion ib faces the passage 34 and the partition 35.

The material to be mixed flowing toward the inlet end a of a nozzle member enters the openings 33 and 34 and is broken into a plurality of streams by the partitions 35. Those streams are brought together in the tapering forward end of the inlet passage and are discharged into the cavity 36 with increased velocity. The material thus passed into the cavity 36 is given a violent swirling motion, and is then discharged through the openings 37 at a high velocity. The material is further mixed as the jets discharged through the separate outlet openings 37 recombine. Each nozzle element by thus repeatedly changing the velocity and direction of movement of the streams flowing through it, causes a. very intimate mixing and remixing of the stream material.

Fig. 6 illustrates a iixed still A', and Fig. 7 illustrates a separate free still B. The stills A' and B are generally similar in construction to the fixed still and free still sections A and B respectively, of Fig. l. As shown, the fixed still A comprises 5 sections exactly like the sections 1, 2, 3, 4, and 5 of the distilling tower or column shown in Fig. l. In Fig. 6, the top section A of the still A is similar in construction to the tower section 10 of Fig. l, and comprising parts 27', 28', 29', and 30', corresponding, respectively, to the parts 27, 28, 29, and 30 of Fig. l. The upper portion of the separate free still B shown in 7, is exactly like the portion above the section 5 of the tower or distilling column shown in Fig. l. In Fig. 7 the column section 6 is superposed on a bottom section 1A exactly like the bottom section 1 of Figs. l and 6. rl`he liquor sprayed into the spray chamber in the section 6 of Fig. 7 is drawn from the space 12A of the section 1A by a steam ejector CB which may be exactly like the steam ejector CA of Fig. l.

The separate stills A and B of Figs. 6 and 7, thus differ from the free and fixed still units of Fig. l only in respect to the upper section 10A of Fig. 6 andthe bottom section 1A of Fig. 7, and in that the section 6 which is included in the fixed still unit A of Fig. 1 is omitted from the fixed still A of Fig. 6, and is included in the free still B of Fig. 7. The liquor discharged through the outlet 13B of the fixed still A is ordinarily passed to waste. The liquor discharged through the outlet nozzle 13B of Fig. 7, however, is passed into the section 10A of the fixed still A' through the liquor supply pipe 27 and spray nozzle 28 of Fig. 6. In some cases there may be a direct pipe connection between the outlet nozzle 13B of the still B and the liquor supply pipe 27 of Fig. 5. In other cases, however, the liquor discharged from the free still B through its outlet 13B is subjected to a dephenolizing treatment in other apparatus, not shown herein, before being passed into the fixed still A through its inlet pipe 27.

As those skilled in the art will recognize, my improved ammonia still columns shown in Figs. l, 6 and 7, are each characterized by the spraying of the liquor to be distilled in a iinely divided or atomized condition into superposed substantially unobstructed spray chambers. Each of the superposed spray chambers of each column still forms part of a continuous gas path extending from the bottom to the top of the still. The gas stream moving through the spray chambers at successively higher levels, consists of steam passed into the lower end portion of the continuous gas passage and the vapors, mainly ammonia vapors distilled out of the ammonia liquor passed into the still at its upper end and liquor is collected in the receivers 12 at the lower ends of the successively lower spray chambers and liquor collected in each receiver is re-sprayed into the chamber above the receiver. In general, the steam content of the gas stream diminishes and the ammonia vapor content of the stream increases as the distance from the lower end of the still increases.

The defiector plates 19, Ztl and 2l form a pervious balile wall or louver F separating the overlapping end portions of the different pairs of adjacent spray chambers with spaces between the plates which may be of ample cross section, relative to the volume of the gas stream, to make the gas pressure drop in each baffle Wall very much smaller than of the drop in pressure of the steam and vapor mixture passing through the liquid sealed orifices at each bubble tray level of the usual bubble still customarily used, heretofore, in distilling ammonia. The fine subdivision of the ammonia liquor sprayed into the spray chambers of my improved ammonia stills, insures a liquor and Vapor contact action in each spray chamber of much greater magnitude than is obtainable in a conventional bubble type still section of the same volumetric capacity.

Ammonia stills formed with superposed spray chambers and means for spraying liquor into each spray chamber and having the general operating characteristics of the stills shown in Figs. 1 5, 6 and 7, may take various forms, some of which are quite different from those shown in Figs. l-7. Some such modifications are shown by way of example, in Figs. 8 to l0, illustrating a free ammonia still comprising a tower or column formed of superposed cylindrical wall sections 4t), 41, 4Z, 43, 44 and 45. The upper sections 44 and 45 surround a spray chamber like the uppermost spray chamber of Fig. 1, except that the distributor 29 of Fig. l is omitted. Cold feed liquor is sprayed into the upper spray chamber of Fig. 8 through a spray nozzle EA centrally disposed in the upper end portion of the section 45 and carried at the iower end of a vertical portion of a feed pipe 46 which extends into the tower through its upper end head. The spray nozzle EA discharges a downwardly directed spray, and the liquor sprayed is collected in a receptacle 12C which does not differ significantly from the receivers 112 of Fig. l. A louver F, comprising louver plates arranged as in Fig. l, is interposed between the uppermost spray chamber of Fig. 8 and the next lower spray chamber which has its receiver 112C in the tower section 43. That receiver receives the liquor collected in the receiver 12e of tower section 44 through a drain pipe G.

The spray chamber having its receiver 12C in section 43 differs from the spray chambers of Fig. l in having the liquor withdrawn from that receiver through the inlet pipe 17a of the pump CB returned to the same section 43, through the pump outlet pipe 18a. The pump CB is a low head pump, and its outlet pipe 18a extends horizontally into the section 43 through a nozzle 13D at a level but slightly above the top of the receiver 12. The inner end of the pipe 18 carries an upwardly directed spray nozzle E located at a level appreciably below the top of the adjacent louver F. The nozzle 13D is of a diameter adapting it for use as a manhole through which the adjacent louver F and subjacent receiver 12 may be inspected and cleaned. The piping connected to the associated pump CB is arranged for the ready disconnection of so much of the piping as is necessary or desirable to facilitate the separation of the end head 16A from the nozzle 13D, and the withdrawal of the portion of the pipe 18a, normally projecting through the nozzle into the distilling column, to thus provide access to the adjacent louver F and receiver 12. With the nozzle 13D providing a manhole opening, the nozzle 13C through which the inlet pipe of the pump CB is connected to the associated receiver 12, is of reduced size, and may well be of the same diameter as the pump inlet pipe 17a.

Liquor overliows from the receiver 12 in the chamber 43 through a pipe G into the receiver 12 of the subjacent spray chamber which is located in the tower section 42. The last mentioned spray chamber is shown as similar to the spray chamber having its receiver 12 in the tower section 43. The arrangement of the circulating pumps CB for the two spray chambers just described, have a practical advantage over the circulating provisions including the pump C of Fig. l, in a reduction in the necessary length of the outlet pipes 18a of Fig. 8, and in a reduction in the net liquid head against which each pump CB of Fig. 8 must operate. The manhole openings formed by the nozzles 13D of Fig. 8 are somewhat more conveniently located for cleaning and inspection purposes than are the manhole openings through the nozzles 13 of Fig. l. There is some practical advantage also, in having the inlet and outlet pipes of each pump CB connected to the same cylindrical wall section, instead of having them connected one to one and the other to the second of two wall sections as they are in Fig. l.

The still shown in Fig. 8 comprises two spray chambers below the spray chamber having its receiver 12 in the section 42. The two lower spray sections have liquor recirculating provisions including steam ejector devices located in the tower sections 41 and 40, respectively. The tower section 41 is provided with a liquid receiver 12D in the form of a shallow pan coaxial with the tower and somewhat smaller in diameter than the latter. The pan 12D is supported on horizontal bars 47 in the section 41 having their ends welded or otherwise attached to the shell of the section. Liquor dropping down through the spray chamber above the pan 12D is diverted into the latter by a funnel like member 48. The latter is in the form of a hollow, inverted, truncated cone with its upper edge in contact with, and welded or otherwise secured to the cylindrical wall of the section 21.

A steam ejector device 49 has its base resting on the bottom wall of the pan 12D and is formed with a steam channel 50 terminating in a central uprising nozzle 51 and discharging into a mixing chamber 52. Steam is supplied to the channel 50 through a supply pipe 53 extending through the tower wall. The mixing chamber 52 is formed with ports at its lower end through which liquor passes into the mixing chamber from the liquor space in the pan 12D surrounding the member 49. The jet of steam discharged through the nozzle 51 and the liquor which the jet moves upward out of the mixing chamber 49 pass through an uprising discharge nozzle 54 forming an outlet from the mixing chamber 52 and discharging into the lower end of a vertical tubular portion 55 of the ejector.

The tubular part 55 has an internal diameter substantially greater than the internal diameter of the nozzle 54. The expanding mixture of steam and entrained liquor moving upward through the tubular part 55 impinges against an inverted detlector cone 57 shown as coaxial with the tube S and supported by the latter through rod like parts 57. The liquor circulating ejector 49 is simple in construction, effective and relatively inexpensive. The steam supplied to the ejector device 49, and to the generally similar ejector device 49a in the tower section 40, subjects the descending feed liquor to necessary heating and evaporation effects.

The ejector' 49a in the tower section 40 comprises parts and features 50', 51', 52', 53', 54 and 55 substantially like the previously mentioned parts and features 50 to 5S, respectively. The device 49a is intended to pass more n :.3 steam, and has larger steam pasages, than the device 49. The device 49a rests on the bottom wall of the tower shown in Figs. 8 and 9, and its mixing chamber 52 receives liquor collecting in a space 12A like that at the lower ends of the stills shown in Fig. l and Fig. 6. Liquor overliowing the vertical partition 22 extending up from the bottom of the bottom wall of the tower shown in Fig. 8, is discharged through an outlet nozzle 13B into a pipe which leads to a xed still, directly in some cases, and through phenolizing apparatus in other cases.

The tower shown in Fig. 8 may be adapted for use as a fixed still with no significant change other than in the piping supplying feed liquor to the nozzle EA and the closure of its steam supply pipe 26. Thus, a mixture of cold ammonia liquor and lime may be added by a branch HA to the liquor passing to the top of a fixed still through the main ammonia liquor supply pipe 46 as is shown in Fig. l2. An alternative arrangement for supplying cold liquor and lime to the top of a xed still is shown in Fig. l1, wherein cold ammonia liquor passes to the inlet of a mixing nozzle I through a feed pipe 60 having its discharge end terminating in a nozzle 61. The latter discharges into a mixing chamber 62 having its outlet connected to the inlet end of the mixing nozzle I, and having a lateral inlet to receive lime through a valved lime supply pipe 63. The vapor outlet 30 from the upper end of the tixed still tower shown in Fig. ll may be arranged to pass the ammonia containing vapor discharged through said outlet pipe may be passed to the steam inlet 26 of a free still such as that shown in Fig. 6 or in Fig. 8. Vapors issuing through the vapor outlet 30 of the free still shown in Fig. 8 are ordinarily passed to a dephlegmator as described in connection with Fig. l.

Fig. 12 illustrates a xed still having superposed cylindrical wall sections 70, 71, 72, 73 and 74, and formed with an upper spray chamber similar to the upper spray chamber of Fig. 8, and having three subjacent spray chambers with their receivers 12 located in the tower sections 72, 71 and 70, respectively. Each of the three last mentioned spray chambers is practically identical in construction with each of the two spray chambers of Fig. 8 with which pumps CB are respectively associated, and similar parts shown in Figs. 8 and l2 are designated by the same reference symbols. The upper spray chamber of Fig. l2 is associated with a circulating pump CB having its inlet pipe 17a connected to the uppermost receiver 12 through a nozzle 13C. The outlet pipe 18e of the uppermost pump CB of Fig. l2 is vertically elongated, and has its transversely bent upper end portion opening into the upper end portion of the tower through the wall of section 74. The pipe 18e` carries at its inner end a down turned spray nozzle E. As shown, the upper nozzle E of Fig. l2 is arranged below the nozzle EA at some distance away from the axis of the tower.

As shown in Figs. 13 and 14, the detlector plates 21a immediately above the receivers 12C in the tower sections 72 and 70 have their lower portions extended to cover the respective subjacent receivers 12C except Where a sector like portion of each plate is cut away along severance lines 21C. The plate 2lb above the receiver 12C of the section 71, similarly extends over the receiver 12C except where a sector shape portion is cut away along severance lines 21d. The cut away sector portions of the plates 21 and 2lb may be similar in shape and size, each having a peripheral arc somewhat smaller than The cut away portions of the plates 21a and 2lb are displaced in opposite directions, however, from the vertical plane including the axis of the tower and the axes of the outlet nozzles 13C through which liquor is withdrawn from the different receivers 12e. A vertical partition plate 211 has its upper edge welded or otherwise secured to the plate 2lb adjacent its line 21d nearest to said plane. The lower edge of the partition plates 21e and 21f is above the outlet 13C from the adjacent receiver 12C.

Each plate 21e is displaced from the above mentioned plane far enough so that the plate may act to insure that most of the liquor withdrawn from the subjacent receiver 12C will be liquor which has entered the receiver through the overflow pipe from the next highest receiver 12o. In consequence, the liquor entering each receiver 12e through the sector shape notch in the corresponding plate 21a will normally pass in large part, at least, to the subjacent receiver 12C through the corresponding overflow pipe G.

The plate 211 attached to the plate 2lb serves to insure that most of the liquor entering the subjacent receiver 12e through the overflow pipe entering into that receiver will pass away from the receiver through the corresponding outlet 13C, while the liquor entering the receiver through the notch in the plate 2lb will pass to the subjacent receiver 12C through the corresponding overflow pipe. The fact that the sectors cut out of the plates 21a and 2lb are displaced to opposite sides of the above mentioned plane is of course explained by the fact that the overflow pipes G at different levels are staggered as shown in Fig. 7.

In Fig. 12, each of the pumps CB is shown as located at a level appreciably below the outlet 13C to which the inlet pipe of the pump is connected. This insures a desirable pressure head on the pump inlet in normal operation, which is specially advantageous in pumping liquid at an elevated temperature. In practice, the pumps C and CB shown in other figures may advantageously be located at levels appreciably lower than the sources of liquor passing to the pump inlets.

Fig. l illustrates a modification of the upper portion of the tower or distilling column shown in Fig. l2 necessary to adapt that still to use with a free still. To that end, in Fig. l5 the uppermost pump CB of Fig. l2 is omitted, and all the liquor collected in the uppermost receiver I2C of Fig. l5 is passed to the subjacent receiver 12C in the section 72 through the overflow pipe G extending between the two receivers.

The attainment of the full advantages of the present invention requires the spraying of the finely subdivided liquor into unobstructed scrubbing spaces, each of a vertical extent substantially greater than the vertical distance between the adjacent bubble trays of the typical ammonia still now in general use. In such bubble still, the Vertical extent of the space between adjacent superposed trays is substantially less than the tower diameter. In the preferred form of my improved still, the vertical extent of each scrubbing chamber is appreciably greater than the tower diameter. Thus, for example, in a practical fixed still of the type and form shown in Figs. 12-14, the overall height of the tower is 39 feet, the outside diameter of the tower is 31/2 feet, and the vertical distance `between the tops of adjacent superposed receivers 12C is 71A feet.

While the precise dimensions just stated are not critical, they are of the character required for the effective dispersion of the atomized liquor sprayed into each scrubbing space, and for a suitably prolonged average period of exposure of each liquor droplet to contact with the ascending vapor stream, for the transfer to the vapor stream of a large portion of the available free ammonia content of the droplet.

It is noted that in a practical still of the type and form shown in Figs. 12-14, the maximum reduction in the cross sectional area of the vapor flow path is a 50% reduction which occurs at the levels of the tops of the receivers 12C. Each of the latter extends from one side of the tower to the central vertical plane including the tower axis.

Whether the liquor is sprayed upwardly into the lower portion of each scrubbing space or is sprayed downwardly into the upper portion of each scrubbing space, the time required for the return of the spray particles to the collecting space at the bottom ofthe scrubbing space is increased as a result of the fine subdivision of the spray liquor. The fine subdivision of the liquor so reduces the mass of each spray liquor particle relative to its external surface, that the lloatative action on the liquor particles of the upilowing steam and vapor stream neutralizes an appreciable portion of the tendency of gravitational action to move particles downward. The fine subdivision of the liquor particles also expedites the escape of ammonia molecules from the droplets by increasing the ratio of the surface area to the mass of the droplets, and by shortening the average distance in the droplet through which the escaping ammonia molecules must pass to reach the droplet surface.

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims,.and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. An ammonia still comprising a vertically elongated tank with an ammonia liquor inlet at its upper end and a steam inlet at its lower end and surrounding a plurality of vertically displaced, substantially unobstructed scrubbing spaces each having a vertical length greater than the diameter of the tank and formed with a separate liquid collecting chamber at the lower end of each scrubbing space and a vapor passage alongside the collecting chamber, a louver structure above each collecting chamber and arranged to deflect into the latter liquid moving downward toward the passage alongside that collecting chamber through the adjacent scrubbing space above that chamber, said louver structure being formed with openings for the passage of gas into said adjacent scrubbing space from the gas passage alongside the last mentioned chamber, conduit means for passing liquor collected in each collecting chamber into a subjacent chamber, a separate spray nozzle located in one end portion of each of said sections and spraying liquor toward the other end of the section to thereby disperse liquor in finely divided form throughout a major portion of the horizontal and vertical extent of said scrubbing space, and pumping means for passing liquid under pressure to each spray nozzle from the subjacent collecting chamber.

2. An ammonia still as specified in claim l, in which said conduit means forms an overflow outlet from each upper collecting chamber through which liquid drains into each lower collecting chamber from the collecting chamber above it.

3. An ammonia still as specified in claim l, in which each louver structure comprises a plurality of horizontally extending, parallel, plate like, elements downwardly inclined toward the subjacent collecting chamber and having their ends secured to the tank wall, each upper louver element having its lower edge horizontally displaced farther from the side of the tank wall adjacent the collecting chamber than the lower edge of each lower louver element of the louver structure.

4. An ammonia still as specified in claim l, including a separate pump for withdrawing liquor from each collecting chamber and for passing the liquor so withdrawn t0 the said spray nozzle spraying the liquor into the said scrubbing space above said chamber.

5. An ammonia still as specified in claim l, in which each of one or more of said spray nozzles is arranged to discharge an upwardly directed spray stream into the lower portion of the scrubbing space above the collecting chamber from which the liquor sprayed through said spray nozzle is withdrawn.

An ammonia still as specified in claim l, in which the cross sectional area of the vapor passage alongside each collecting chamber is not smaller than about one-half the cross sectional area of the tank.

7. An ammonia still as specified in claim l, for use as a fixed ammonia still, and comprising means adding an alkali liquor to the ammonia liquor withdrawn by the pumping means from a collecting chamber in the upper portion of the fixed still and passed under pressure to a spray nozzle arranged to spray liquor into the scrubbing space above the collecting chamber from which the liquor is withdrawn.

8. An ammonia still as specified in claim 7, in which a separate pump has its inlet pipe connected to the said collecting chamber in the upper portion of the fixed still and has its outlet connected to the spray nozzle discharging into the scrubbing space of said collecting chamber, and in which mixing means are included in said outlet pipe and in which the latter is formed with an inlet for alkali liquor between said mixing means and said pump.

An ammonia still comprising a vertically elongated tank with an ammonia liquor inlet at its upper end and a steam inlet at its lower end and surrounding a plurality of vertically displaced, substantially unobstructed scrubbing spaces each having a"vertical length greater than the diameter of the tank and formed with a separate liquid collecting chamber at the lower end of each scrubbing space and a vapor passage alongside the collecting chamber, a louver structure above each collecting charnber and arranged to deflect into the latter liquid moving downward toward the passage alongside that collecting chamber through the adjacent scrubbing space above that chamber, said louver structure being formed with openings for the passage of gas into said adjacent scrubbing space from the gas passage alongside the last mentioned chamber, conduit means for passing liquor collected in each collecting chamber into a subjacent chamber, a separate nozzle located in one end portion of each of said sections and spraying liquor toward the other end of the section to thereby disperse liquor in finely divided form throughout a major portion of the horizontal and vertical extent of said scrubbing space, and pumping means for passing liquid under pressure to each spray nozzle from the subjacent collecting chamber, said unobstructed scrubbing spaces collectively forming an aggregate scrubbing space having a maximum vertical extent substantially greater than the maximum horizontal extent of the tank.

References Cited in the file of this patent Number UNITED STATES PATENTS Name Date Turner July 16, 1872 Meyer Jan. 24, 1905 Unger June 6, 1911 Marquard et al May 15, 1923 Collins July 26, 1932 Danforth Aug. 30, 1932 Shoeld Sept. 20, 1932 Glenn Sept. 5, 1933 Pyzel Oct. 1,5, 1935 Shoeld Aug. 3, 1937 

9. AN AMMONIA STILL COMPRISING A VERTICALLY ELONGATED TANK WITH AN AMMONIA LIQUOR INLET AT ITS UPPER END AND A STEAM INLET AT ITS LOWER END AND SURROUNDING A PLURALITY OF VERTICALLY DISPLACED, SUBSTANTIALLY UNOBSTRUCTED SCRUBBING SPACES EACH HAVING A VERTICAL LENGTH GREATER THAN THE DIAMETER OF THE TANK AND FORMED WITH A SEPARATE LIQUID COLLECTING CHAMBER AT THE LOWER END OF EACH SCRUBBING SPACE AND A VAPOR PASSAGE ALONGSIDE THE COLLECTING CHAMBER, A LOUVER STRUCTURE ABOVE EACH COLLECTING CHAMBER AND ARRANGED TO DEFLECT INTO THE LATTER LIQUID MOVING DOWNWARD TOWARD THE PASSAGE ALONGSIDE THAT COLLECTING CHAMBER THROUGH THE ADJACENT SCRUBBING SPACE ABOVE THAT CHAMBER, SAID LOUVER STRUCTURE BEING FORMED WITH OPENINGS FOR THE PASSAGE OF GAS INTO SAID ADJACENT SCRUBBING SPACE FROM THE GAS PASSAGE ALONGSIDE THE LOST MENTIONED CHAMBER, CONDUIT MEANS FOR PASSING LIQUOR COLLECTED IN EACH COLLECTING CHAMBER INTO A SUBJACENT CHAMBER, A SEPARATE NOZZLE LOCATED IN ONE END PORTION OF EACH OF SAID SECTIONS AND SPRAYING LIQUID TOWARD THE OTHER END OF THE SECTION TO THEREBY DISPERSE LIQUOR IN FINELY DIVIDED FORM THROUGHOUT A MAJOR PORTION OF THE HORIZONTAL AND VERTICAL EXTENT OF SAID SCRUBBING SPACE, AND PUMPING MEANS FOR PASSING LIQUID UNDER PRESSURE TO EACH SPRAY NOZZLE FROM THE SUBJACENT COLLECTING CHAMBER, SAID UNOBSTRUCTED SCRUBBING SPACES COLLECTIVELY FORMING AN AGGREGATE SCRUBBING SPACE HAVING A MAXIMUM VERTICAL EXTENT SUBSTANTIALLY GREATER THAN THE MAXIMUM HORIZONTAL EXTENT OF THE TANK. 